Online, but wireless router doesn't see Vista Machine

I'm well into my second month with Vista, and aside from the "calculating
time remaining" fiasco (the fact that there isn't a fix yet just blows my
mind), things have been going pretty well...

Until tonight.

I opened up my trusty copy of WS_FTP LE, which I've been using with no
problems on Vista. Suddenly, tonight, every FTP site I try to connect to
times out.

I'm stumped, but eventually I log into my router's admin software (Netgear
RangeMax 240 -- I don't recommend it) and check the "attached devices" table.
There's no sign of the Vista computer (a Thinkpad T60).

Now, ever since I got this Vista computer it has shown up in the router's
"attached devices" table under the name "--" instead of the network name I
gave it, "T60." All the other computers on the network (both Mac and XP) see
it as "T60," but the router only ever saw it as "--."

Tonight, however, the router isn't showing it as connected at all. But it is
connected. I'm using it right now.

So, since the router doesn't know that the Vista machine is connected, it
seems unable to route FTP replies back to it, which (I have to assume) is why
I'm timing out when I try to connect to FTP sites.

I have no idea how the HTTP requests are working. I'm not really very
knowledgable about this stuff. Since PuTTY (SSH) is working just fine, I have
to assume it has something to do with Passive Transfers in FTP. But all of
the FTP servers I use require passive mode, so I can't switch it off to test.

Maybe this is a router issue, in which case I'm just going to go out
tomorrow and buy a Linksys router, because I'd rather pull my own teeth with
a rusty pair of pliers than deal with Netgear's abysmal customer service. But
maybe it's a Vista thing that I just haven't learned about yet.

I'm hoping someone out there can throw their two cents my way.

Thanks.